As sniffles, coughs, and fevers become more common during flu season, it's easy to assume that any symptom we experience these days is caused by the flu. However, while the flu can be a highly probable cause, these symptoms could also indicate a common cold, another viral illness that can strike all year round.

The flu and common cold are respiratory tract infections caused by viruses. They are both contagious and share similar symptoms and transmission methods, making it hard to tell them apart. Despite their similarities, there are key differences that can help us distinguish between the two. So, how can we tell the difference?

In this article, we’ll explore these differences and learn how to identify whether you're dealing with the flu or a common cold.

 

Key Differences Between the Flu and Common Colds

Cause:

The flu and colds are caused by different types of viruses.

The flu, or influenza, is caused by influenza viruses only, primarily types A and B. These viruses are highly contagious and can spread rapidly through communities, especially during flu season.

The common cold is caused by a variety of viruses, with rhinoviruses being the most common culprits. There are over 200 different viruses that can cause a cold, which explains why colds are prevalent year-round.

 

Signs and Symptoms:

Cold symptoms are usually less severe than the flu.

The common cold typically causes mild illness with symptoms mainly affecting the nose and throat only. Its characteristic symptoms include a runny and stuffy nose (nasal congestion), sneezing, and a sore throat.

The flu, on the other hand, affects the whole body. It typically starts with a high fever and involves severe body aches, fatigue, headache, and chills, which can significantly impact one’s daily activities. In this sense, the flu is considered more serious than the common cold.

It is important to note that despite the differences in characteristic symptoms, both the flu and colds share a lot of similar symptoms, which vary only in severity and duration.  According to the Centers for Disease Control and Prevention (CDC), below are the key differences in symptoms between the flu and colds.

 

 

Signs and Symptoms

Common Cold

Influenza (Flu)

Fever*

Rare (usually low-grade only)

Common (usually high)

Body aches

Slight

Common (usually severe)

Chills

Uncommon

Fairly Common

Fatigue, Weakness

Sometimes (mild and brief)

Common (last 2-3 weeks)

Sneezing

Common

Sometimes

Chest discomfort, Cough

Mild to moderate (hacking)

Common (can become severe)

Runny or stuffy nose

Common

Sometimes

Sore throat

Common

Sometimes

Headache

Rare

Common

*Although fever is common with the flu, not everyone with the flu will have a fever

 

Symptom Onset:

Cold symptoms develop gradually, whereas flu symptoms appear suddenly.

Cold symptoms develop gradually over 2-3 days after exposure to the virus and typically last about seven to ten days. However, symptoms like a cough or runny nose can persist for a few weeks.

Flu symptoms come on suddenly, often within 1-4 days after infection, and last 1-2 weeks. Some people may continue to feel fatigued for several weeks after recovering from the flu.

 

Complications:

Common colds are less likely to cause complications than the flu.

While colds can be uncomfortable, they rarely lead to serious complications. When complications do happen, they usually include secondary infections such as sinusitis or ear infections.

The flu can lead to serious complications, especially in young children, older adults, pregnant women, and individuals with underlying health conditions. Complications can include pneumonia, bronchitis, sinus infections, and worsening of chronic medical conditions, which can lead to hospitalizations.

 

Treatment:

Antiviral medications are available for the flu, but no antiviral treatment exists for the common cold.

There is no cure for either the flu or colds.  Both illnesses have to run their course with just rest, plenty of fluids, and some over the counter (OTC) medications to relieve symptoms.

However, antiviral medications are available for the flu that can help reduce the severity and duration of symptoms. These are typically prescribed to high-risk individuals within the first 48 hours of symptom onset.

On the other hand, there is no specific antiviral treatment for the common cold. Treatment focuses on symptom management with OTC medications to alleviate symptoms like congestion, sore throat, and cough, along with rest and adequate hydration.

 

Prevention:

Vaccines are available for the flu, but there is no vaccine for the common cold.

The best way to prevent the flu is to get an annual flu vaccine. Flu vaccines are designed to protect against the most common strains of the virus each year. In addition, good hygiene practices such as regular handwashing, covering coughs and sneezes, and avoiding close contact with sick individuals can help reduce the spread.

There is no vaccine for the common cold due to the large number of viruses that can cause it. The best way to prevent it is to focus on good hygiene practices similar to those for the flu, avoid close contact with infected individuals, and maintain a healthy immune system through proper diet, exercise, and sleep.

 

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